Various types of fibers having two or more cross-sectional components (ie multi-component fibers) are well known in the art, as are processes for their production. Examples of such fibers and production processes are set forth in U.S. Pat. Nos. 4,233,355 and 4,460,649.
Multicomponent fibers have been used to generate micro- or ultrafine filaments (see, for example, U.S. Pat. Nos. 4,233,355, 4,966,808, 5,124,194 and 5,366,804). The fibers can be split into their components using mechanical or chemical (eg solvent) means. In U.S. Pat. No. 4,233,355, for example, microfibers are generated from multicomponent (composite) fibers by selective dissolution of one of the components of the composite fiber using a solvent in which the microfibrous component is relatively insoluble.
The art does not include a description of a method of producing a fiber of virtually any cross sectional shape from a composite fiber having a preselected relative arrangement of components of differing solubility in a given solvent. The present invention provides such a process.